A conventional full-duplex communication has been widely employed, as a wireless communication mode, between mobile devices such as mobile phones and smartphones. Examples of a full-duplex communication mode encompass a frequency division duplex (FDD) mode and a time division duplex (TDD) mode.
Patent Literature 1, which will be later described, discloses a technique related to a mode selection of a dual-mode wireless device that is shared by the TDD mode and the FDD mode. The following description will briefly discuss, with reference to FIG. 7, the wireless device disclosed in Patent Literature 1. FIG. 7 is a circuit diagram illustrating a configuration of the wireless device disclosed in Patent Literature 1.
According to the TDD mode of the wireless device disclosed in Patent Literature 1, in a circulator 20, (i) a transmission signal is supplied from a third terminal 26 to a first terminal 22 and (ii) a received signal is supplied from the first terminal 22 to a second terminal 24 (see FIG. 7). Further, according to the FDD mode of the wireless device, in an antenna sharing device 10, (i) a transmission signal is supplied from a transmitter-receiver terminal 14 to an antenna terminal 12, and (ii) a received signal is supplied from the antenna terminal 12 to a reception terminal 16. According to Patent Literature 1, the wireless device switches between the TDD mode and the FDD mode with use of the antenna sharing device 10 and the circulator 20.